From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.devel Subject: Re: Why is there no `until' in elisp? Date: Fri, 19 Oct 2018 11:28:02 -0400 Message-ID: References: <87murdu6to.fsf@portable.galex-713.eu> <877eihbt1y.fsf@ericabrahamsen.net> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1539963067 28299 195.159.176.226 (19 Oct 2018 15:31:07 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 19 Oct 2018 15:31:07 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.0.50 (gnu/linux) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Oct 19 17:31:02 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gDWju-0007Fw-8o for ged-emacs-devel@m.gmane.org; Fri, 19 Oct 2018 17:31:02 +0200 Original-Received: from localhost ([::1]:51129 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gDWm0-0002BI-S6 for ged-emacs-devel@m.gmane.org; Fri, 19 Oct 2018 11:33:12 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:45327) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gDWlK-00027a-5T for emacs-devel@gnu.org; Fri, 19 Oct 2018 11:32:34 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gDWlB-0003JH-3v for emacs-devel@gnu.org; Fri, 19 Oct 2018 11:32:27 -0400 Original-Received: from [195.159.176.226] (port=49712 helo=blaine.gmane.org) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gDWlA-00038y-SM for emacs-devel@gnu.org; Fri, 19 Oct 2018 11:32:21 -0400 Original-Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1gDWiz-00062A-2g for emacs-devel@gnu.org; Fri, 19 Oct 2018 17:30:05 +0200 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 15 Original-X-Complaints-To: usenet@blaine.gmane.org Cancel-Lock: sha1:xS40SJc+k4Q0xBpFFZlOrB5h1Sw= X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 195.159.176.226 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:230494 Archived-At: > I have nothing to do with this, but my feeling is that Lisp developers > in general drag their feet about adding trivial/obvious constructs to > the standard library. As your footnote makes clear, it's a two-line code > addition to make `until' work. There are different schools of thought > about this: one that says "why?", and one that says "why not"? The "why > not"s contribute to subr.el and subr-x.el :) Personally, I grew fond of `until` and wanted to add it (even went to the trouble of writing the corresponding byte-compiler code), but really in 99% of the cases, you can just negate the test so the benefit in minuscule. But if we could go back in time, then I would definitely replace `while` with `until`. Stefan